1. O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Preparation and characterization of single-crystal diamond for improved particle detectors
O.Lysenko, N.Novikov, V.Grushko, O.Zanevskiy, M.Serga, V.Lysakovskiy, S.Ivakhnenko
V.Bakul Institute for Superhard Materials of the National Academy of Sciences of Ukraine

2. Single crystal diamond
O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Motivation
property
silicon
Polycrystalline
diamond
Single crystal diamond
detector operation
band gap [eV]
breakdown voltage [V/cm]
intrinsic resistivity [Ω/cm] electron mobility [cm2/Vs] hole mobility [cm2/Vs]
1.12
3∙105
2.3 ∙ 105
1350
480
5.4
0.5 ∙ 106
>> 106
1800
1000
5.48
107
>> 1011
1900 – 4500
1800 – 3500
+ high T operation
+high field operation
+ low leakage current
+ fast signal
Evolution of detectors for experiments at high luminosity colliders
Silicon
Polycrystalline
diamond
films
CVD single
crystal diamond
Ultrapure HPHT single crystal
diamond with controlled
physical properties

3. Difficulties on the way towards a perfect diamond detector
O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Difficulties on the way towards a perfect diamond detector
Ideally diamond detector is just
a solid state ionization chamber
In reality next problems exit:
nitrogen limits the life time
of free charge carriers
defective surface layer creates undesirable space charge
To improve the quality of diamond detectors following approach is used:
Specified conditions of HPHT diamond growth with low defect content
Thermobaric processing of HPHT diamonds
Cut diamond plate from defined area of the crystal

4. Idea The band structure of diamond
O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Idea
The band structure of diamond
S. Painter, D. E. Ellis, A. R. Lubinsky, Ab Initio Calculations of the Electronic Structure and Optical Properties of Diamond Using the Discrete Variational Method, Phys. Rev. B, vol. 4, p. 3610, 1971

5. Approach 1) Synthesis of colorless large HPHT IIa diamonds
O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Approach
1) Synthesis of colorless large HPHT IIa diamonds
2) Cut diamond plate from defined area of the crystal
3) Specified conditions of
crystal growth

6. Termobaric processing
O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Termobaric processing
Nitrogen is the main impurity in diamond
C-defects (nitrogen in replacing position)
prevail in synthetic diamonds
Thermobaric processing allows to convert
C-defects into (less harmful) A-defects
P = 6.7GPa
T = 1800C
t = 4 hours
Conditions of thermobaric processing:
Types of defects are seen in IR absorbtion spectra:
C-defect: cm-1
A-defect: cm-1

7. O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
HPHT diamond plates

8. Future work O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Nitrogen vacancies are actually fluorescent: when green light strikes them, the nitrogen atom’s two excitable unpaired electrons glow a brilliant red.
The realization of electrically driven single-photon source based on a single neutral nitrogen-vacancy centre in a diamond diode structure.
a) L. Jiang, ect Repetitive Readout of a Single Electron Spin via Quantum Logic. with Nuclear Spin Ancillae Science 326, 267 (2009).
b) N. Mizuochi, ect Electrically driven single-photon source at room temperature in diamond. Nature Photonics, Volume 6, Issue 5, pp (2012).

9. O. Lysenko - WPCF 2013, 5-8 November 2013, Acireale, Italy
Summary
HPHT single crystal diamond is a good candidate for diamond detectors of particles. HPHT diamond plates have advantages over commonly accepted CVD plates due to absence of highly defective intercrystallite boundaries. Specified conditions of crystal growth allows to obtain detectors with very low defect content thus avoiding undesirable space charge. Cutting a diamond plate from specific zone of the crystal with extremely low nitrogen content allows to produce detectors with contain of nitrogen less then 1015 atoms per cubic centimetre.
The structure of single-crystal diamond with a low nitrogen content should be Control using NV-centers approach. When exposed to the NV-centers by the specific electromagnetic radiation, they become a single-photon sources. According to the number of observed single-photon sources it can be concluded about the concentration of nitrogen and accumulated radiation.
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